Final answer:
Inverse proportionality is the least likely pair of quantities to be directly proportional.
Step-by-step explanation:
The pair of quantities that is least likely to be directly proportional is one variable increases, the other variable decreases by a greater amount. This is an inverse proportionality relationship. Inverse proportionality occurs when a change in one variable leads to the opposite change in the other variable. For example, if the price of a product increases, the demand for the product decreases by a greater amount.